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Finding sum of n terms
Last updated at Aug. 3, 2021 by Teachoo
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Ex 5.3, 1 Find the sum of the following APs. (i) 2, 7, 12 ,ā¦., to 10 terms. 2, 7, 12,ā¦., to 10 term s We know that Sum of AP = š/2 (2a + (n ā 1) d) Here n = 10, a = 2, & d = 7 ā 2 = 2 Putting these in formula , Sum = š/š (2a + (n ā 1) d) = 10/2 (2 Ć 2 + (10 ā 1) Ć 5) = 5(3 + 9 Ć 5) = 5 (4 + 45) = 5 (49) = 245